In digital media distribution systems, such as Multi-Service Operator (MSO) cable systems or Telco Internet Protocol Television (IPTV) systems, a program content feed is transmitted by a content owner to local media distributors for distribution to subscribers. Typically, the program content feed contains embedded cues to signal when local advertising program content may be inserted into the content feed. Additionally the program content feeds or video on demand (VoD) files may also employ embedded cues to signal when personalized or localized national level advertising may be inserted.
In traditional analog media distribution systems, such cues are provided as a predetermined inaudible analog tone. With the introduction of digitally encoded media, corresponding digital cues were developed, primarily based on the needs of MSO cable system operators. Some providers have attempted to introduce the analog cues into the digital systems by generating the analog cues based on the digital cues however, this approach sacrifices most of the information contained in the digital cues and falls back to the most primitive timing approaches, which is not suitable for some digital systems.
As additional digital encoding and transmission systems and formats (such as IPTV) have been deployed, the need for transcoding or re-encoding digital compressed media (e.g., to a lower bit rate to accommodate Telco access networks that have relatively limited available bandwidth) has raised a number of issues. One such issue is that the DPI cues relied on for insertion of local advertising content are frequently removed during the re-encoding process and are lost and unrecoverable. As a result, the distributors of digital media who must re-encode the digital compressed media have adopted a fall back position of performing ad insertion only on channels that still use analog cues which are not lost during re-encoding. Another issue is that the original program source metadata is lost when the media stream is re-encoded. In particular metadata pertaining to the content of the media stream is not available to the encoder that is re-encoding the media. As such, the encoder doing the re-encoding is not capable of producing digital compressed media that is at the quality level that would have been possible if performed directly by the original encoder.
Accordingly, methods and apparatus enabling metadata to survive re-encoding of the digital media remain highly desirable. Methods and apparatus that provide for improved transcoding of digital compressed media are also highly desirable.